Exemplary embodiments of the present invention relate to the art of turbomachine injection nozzles and, more particularly, to turbomachine injection nozzles including a coolant delivery system.
In general, gas turbine engines combust a fuel/air mixture which releases heat energy to form a high temperature gas stream. The high temperature gas stream is channeled to a turbine via a hot gas path. The turbine converts thermal energy from the high temperature gas stream to mechanical energy that rotates a turbine shaft. The turbine may be used in a variety of applications, such as for providing power to a pump or an electrical generator.
In a gas turbine, engine efficiency increases as combustion gas stream temperatures increase. Unfortunately, higher gas stream temperatures produce higher levels of nitrogen oxide (NOx), an emission that is subject to both federal and state regulation. Therefore, there exists a careful balancing act between operating gas turbines in an efficient range, while also ensuring that the output of NOx remains below mandated levels. One method of achieving low NOx levels is to ensure good mixing of fuel and air prior to combustion. However certain fuels, such as hydrogen and syngas, have a high flame speed, particularly when burned in a pre-mixed mode. The high flame speed often results in flame holding that detracts from operating efficiency and has a negative impact on operational life of turbine components.